[Interior, view of air ducts.]

[Heating control valve on 17th floor of unidentified building.]

[Interior, basement with air ducts.]

[Interior, basement with air ducts.]

[Interior, basement with air ducts.]

[Interior, basement with air ducts.]

[Interior, basement with air ducts.]

[Interior, basement with air ducts.]

[Interior, detail of meters.]

533 West 57th Street. Pavelle Laboratories. Interior, detail of machinery and air ducts

533 West 57th Street. Pavelle Laboratories. Interior, detail of machinery and air ducts

[Interior, boiler room.]

[Interior of unidentified building, possibly a factory.]

[Interior, possibly a basement, with unidentified equipment.]

[Interior, boiler room.]

[Interior, boiler room.]

[Interior with machinery.]

[Interior, boiler room.]

[Interior, radiator manufacturing shop.]

60 Wall Street [70 Pine Street.] Cities Service Company. Interior, Riggs-Distler Heat units